Funding is requested for a Bruker Model AM-300 Superconducting Fourier 300 MHz NMR Spectrometer. The users of this instrument are a group of investigators with 14 NIH grants in which NMR is currently used for structure determination. These investigators presently have a 90 MHz spectrometer in house and all 300 MHz spectra are obtained out of house through cumbersome mechanisms which are expensive and delay progress. The 300 MHz instrument will be used extensively in ongoing studies on the identification of carcinogens, their metabolites, and their DNA adducts. The instrument will also allow application of 2D-NMR to these structural problems. The requested instrument is absolutely essential to allow progress in studies on the identification of carcinogens in the environment, their modes of formation, and their mechanisms of activation in experimental animals and man.